Generally, a lens interchangeable camera is configured by a combination of a camera body and an interchangeable lens that is attached to and detached from this camera body. In this case, if the camera body and the interchangeable lens are of the same manufacturer, the interchangeable lens can be directly mounted on the camera body. However, in a case where the standard (manufacturer standard) of the mount part of the camera body is different from that of the mount part of the interchangeable lens due to the difference in the manufacturers of the camera body and the interchangeable lens, direct mounting is not possible. Thus, a mount adaptor is interposed between the camera body and the interchangeable lens to enable mounting. Moreover, the camera body side (including the mount adaptor) has a built-in lens locking mechanism, which locks the mounted interchangeable lens on the camera body side to inhibit falling of the interchangeable lens. On the other hand, a lock releasing device is disposed on the camera body side so that in removing the interchangeable lens from the camera body side, the interchangeable lens can be removed by manually operating the lock releasing device and releasing the lock of the lens locking mechanism.
Conventionally, this type of lock releasing device is mostly configured by a so-called one-point operation method using an operation button or an operation lever. For example, Patent Literature 1 discloses a releasing mechanism that releases a lock by pressing down an attachment/detachment button to cause a lock pin that interlocks with the attachment/detachment button to retract from a mount surface of a camera mount. Patent Literature 2 discloses a releasing mechanism that releases locks by pushing in a lock releasing button to cause a tip of a guide axis to press a pressed part and move a lock pin support member downward along the guide axis against an biasing force of a lock pin biasing spring, and further retreating a tip of a lens lock pin to a disengaged position that is roughly flush with a mount surface on the body side to accommodate it in a lock pin advancing/retreating hole. Patent Literature 3 discloses a releasing mechanism that releases a lock of a lens by pressing a head part of a lock releasing button to cause the lock releasing button and a movable member to move against a spring and cause a lens locking lever to rotate about the axis by a tapered outer peripheral surface of the movable member, and allowing a lock claw of the lens locking lever to come off from the lens that is mounted on a lens mount. Furthermore, Patent Literature 4 discloses a releasing mechanism that releases a lock of a lens by pressing down a mount lock releasing button against an elastic force of a compression coil spring to cause a tip part of an axis to push down a connecting member and allowing a pin to be guided to a cylindrical guide part to pull down a lock pin in its axial direction, thereby pulling down a lens driving pin that interlocks with the lock pin.